网格搜索的迭代的实现（Python）

网格搜索

利用for语句实现

# Input:
>>> n = ['1', '2', '3']
>>> m = ['a', 'b', 'c']

>>> grid_search = [(k, l) for k in n for l in m]

>>> for k, l in grid_search:
>>>   print('k:', k, '; l:', l)

# Output:
k: 1 ; l: a
k: 1 ; l: b
k: 1 ; l: c
k: 2 ; l: a
k: 2 ; l: b
k: 2 ; l: c
k: 3 ; l: a
k: 3 ; l: b
k: 3 ; l: c

其中对grid_search列表变量的定义，相当于如下的for语句：

>>> grid_search = []
>>> for k in n:
>>>   for l in m:
>>>     grid_search.append((k, l))

>>> grid_search
[('1', 'a'), ('1', 'b'), ('1', 'c'), 
('2', 'a'), ('2', 'b'), ('2', 'c'), 
('3', 'a'), ('3', 'b'), ('3', 'c')]